So far I have found the members on this site to be very knowledgeable and helpful, so I am hoping that I might get some advice regarding my father's ancestry, please.

We can only go so far with documents because of an illegitimate line, but we have an idea who the mystery man may have been ~ hence my brother having a 43-marker Y-DNA test carried out. So far, we have found no good matches.

What would help us is if we could at least establish that the line has some Welsh DNA. (The family in question claim ancestry from 'the Welsh princes'.)

Could someone advise us on what to do next with regard to testing ~ or whether anything in our current results is already useful in this respect, please?

Do you have a Ysearch ID? If so, it would be helpful to see who your closest matches are.

IMHO, it is probably impossible at this point to distinguish between Welsh and English DNA, though others might disagree. If you were to do SNP testing, you could determine whether your subclade is one commonly found in Wales. However there is no subclade yet discovered which is unique to Wales.

I agree with Goldenhind, but I would also recommend that your brother upgrade to at least 67 markers, and 111 would be even better. If his closest matches are all or mostly Welsh or men with Welsh surnames, that's probably the best indicator.

As far as SNP testing goes, you might want to consider L21. R-L21 is probably the most common y haplogroup in Wales, although it's not exclusive to Wales, not by a longshot. There's plenty of it in nearby England and in the rest of the British Isles, as well. You might want to wait on any SNP testing, however, until he gets 67 str markers or more. The haplotype can tell you a lot and may be able to point you in the right direction and save you some money on SNP testing.

I had thought about L21 and wondered if it were worth going straight for that or for the upgrade ~ when I've saved up my pennies that is!

I was also wondering about the Genographic Project test and whether that would provide the details that I am looking for, if my brother were to take it, since it seems that it could provide a whole raft of interesting results.

My Mum is Welsh, but with a mixed ancestry, including Irish, English and Greek, as well as Welsh blood, so the 'Geno 2.0' test might provide info on her background, too.

But do you happen to know if it would provide the necessary data regarding my Dad's background, please?

I certainly agree with Rich that more markers are essential for helping to determine your y/line origins. I would start with 67. You can always upgrade to 111 later.

For SNP testing, L21 is an excellent place to begin. It is very common amongst the Welsh, though other R1b subclades are found there as well, and as Rich mentions, L21 is found in other areas of Britain and even on the continent. You can order a stand alone test for L21 from FTDNA for $39.

You may consider Family Finder testing for aDNA matches. From those results you may submit to a Website called Gedmatch.com that extends the ability to find matches and utilize the 'ADMIXTURE-PROPORTIONS ANALYSIS' to see how your Admixiture breaks out with several systems that can calculate various Single and Mixed Mode Population Sharing percentages. My results example shows what type of info can be provided.

Do the results fit with what you already knoew, or were there some surprises?

Do you know how reliable these results are?

Thanks :)

I have a heavy maternal GGrandfather Dutch with Deeper maternal GGgrandmother lineage SE Europe. My paternal is appearing to be UK based and not German as I once understood. My YDNA closest matches are UK/Scot, Isle of Man, Scottish and deeper Irish. Along with 3rd and fouth cousin aDNA matches within the last few generations from and in the Isles and mostly southeastern USA.

All of this is a new science alot done through amateurs who are using comparison data from the latest sources. A genealogical DNA test looks at a person's genetic code at specific locations. Results give information about genealogy or personal ancestry. Generally, these tests compare the results of an individual to others from the same lineage or to current and historic ethnic groups.

You will need to compare known paper to these results and make decisions based on how they both mesh.

Here's something interesting from a recent edition of the Welsh tv program Corff Cymru about the differences between the Welsh and the English. Dr. Grierson found a pretty startling difference between y-dna west and east of Offa's Dyke, the old boundary between Anglo-Saxon Mercia and the Welsh kingdom of Powys, or, more broadly, between Anglo-Saxon England and Wales. As you can see, on the west or Welsh side of Offa's Dyke, L21 runs around 50%, sometimes more. East of Offa's Dyke, in Shropshire, L21 drops to 25% of the total.